title: Quercetin prevents necrotic cell death induced by co-exposure to benzo(a)pyrene and UVA radiation.
abstract: The phototoxicity of low-energy ultraviolet radiation, such as UVA, can be enhanced by the presence of photosensitizing agents. Hence, co-exposure of cells to benzo[a]pyrene (BaP), a widespread environmental carcinogen and photosensitizing agent, and UVA may synergistically induce DNA damage. In this study, exposure of cells to various concentrations of BaP for 1h followed by UVA irradiation (2J/cm(2)) increased DNA damage and decreased cell viability. Expression of apoptosis-related proteins (caspase-9, caspase-3, PARP, and Bax) and hypodiploid DNA content (sub-G(1)) were not changed. LDH release into the culture medium increased in a dose-dependent manner with BaP under UVA irradiation, suggesting that cell death due to BaP/UVA co-treatment occurred via necrosis. Intracellular reactive oxygen species (ROS) levels were increased significantly in the co-exposed cells, and treatment with the polyphenol quercetin, but not with sodium azide or N-acetylcysteine, decreased ROS levels and increased cell viability in BaP/UVA-treated cells. In conclusion, UVA irradiation combined with BaP synergistically promoted necrosis of A549 cells by increasing intracellular ROS levels, and quercetin prevented BaP-enhanced phototoxicity due to UVA irradiation.
authors.affiliation: School of Public Health and Institute of Health and Environment, Seoul National University, 28 Yongon-dong, Jongno-gu, Seoul 110-460, Republic of Korea.
authors.forename: Hae Dong
authors.initials: HD
authors.lastname: Woo
authors.forename: Byeong Mo
authors.initials: BM
authors.lastname: Kim
authors.forename: Yang Jee
authors.initials: YJ
authors.lastname: Kim
authors.forename: Young Joon
authors.initials: YJ
authors.lastname: Lee
authors.forename: Su Jin
authors.initials: SJ
authors.lastname: Kang
authors.forename: Yoon Hee
authors.initials: YH
authors.lastname: Cho
authors.forename: Jun Yeol
authors.initials: JY
authors.lastname: Choi
authors.forename: Hai Won
authors.initials: HW
authors.lastname: Chung
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology*; D001564:Benzo(a)pyrene / Q000008:administration & dosage / Q000633:toxicity*; D016923:Cell Death / Q000187:drug effects / Q000528:radiation effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D004249:DNA Damage / Q000187:drug effects / Q000528:radiation effects; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000187:drug effects / Q000528:radiation effects; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D009336:Necrosis / Q000209:etiology / Q000517:prevention & control; D011794:Quercetin / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D019810:Sodium Azide / Q000494:pharmacology; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species; D001564:Benzo(a)pyrene; D019810:Sodium Azide; D011794:Quercetin; D007770:L-Lactate Dehydrogenase; D000111:Acetylcysteine